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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

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Comments 101851 to 101900:

  1. Ice data made cooler
    John Garrett, A fantastic tool, a job well done. Thanks for this. If I might make one request at this time. Would it be possible to display horizontal scale lines and have the scale adjustable by the user? I realize the mouse-over function allows one to examine each data point-- but it would be nice to get an idea of the values without having to do that. Wish I had your skills John;)
  2. Stratospheric Cooling and Tropospheric Warming
    VeryTallGuy - 212 I didn't talk about the issue of ozone with regard to cooling of the stratosphere. Ozone brings heat into the stratosphere. However, with the thinning of the ozone layer that occured several decades ago, it is now bringing in less heat and this has caused some of the cooling. Bob
  3. Stratospheric Cooling and Tropospheric Warming
    Oh, and meant to add whilst this is interesting, overall for the stratospheric cooling issue all that matters is that UV is absorbed, heating the stratosphere. CO2 enables the heat to be released; more CO2 means more IR radiance at a given temperature, hence increasing stratospheric CO2 reduces stratospheric temperature. I've almost convinced myself now...
  4. Renewable Baseload Energy
    Re: RSVP's last bunch of tro...I mean, comments, I'd be curious to hear how quokka would respond to the "argument" put forth.
  5. Stratospheric Cooling and Tropospheric Warming
    Bob, Oxygen and ozone absorb in different regions of the UV. There's a good overview description of the process here: http://eospso.gsfc.nasa.gov/science_plan/Ch7.pdf "The formation of ozone by the photolysis of molecular oxygen removes most of the incident sunlight with wavelengths shorter than 200 nm. The wavelengths between 200 and 310 nm are removed by the photolysis of ozone itself." - bringing out the point that different wavelengths are involved in the different reactions. For detailed chemistry try here http://www-tonycox.ch.cam.ac.uk/Download/ERCA2_Stratosphere.ppt It's complicated but not conceptually difficult I think.
  6. Renewable Baseload Energy
    Looks like deniers are getting desperate. Is it because of recent wikileaked cables showing the US and China collaborated to make sure Copenhagen would be a failure? One thing's for sure: Cablegate has completely eclipsed Climategate, even as far as climate is concerned. To deniers and politically-motivated skeptics, I say: welcome to 2011. You've got your work cut out for you. :-) As far as nuclear goes, I can understand why some in the US would support China building more NPP. After all, that almost certainly means more money for Westinghouse.
  7. How to explain Milankovitch cycles to a hostile Congressman in 30 seconds
    Daniel... That's fantastic. I love the very last comment that Alley makes. "The economic models say if you're really worried about uncertainties you put more money on the table."
  8. Ice data made cooler
    Thank you for your comments. I have a full day ahead of me, and I'm doing an astronomy presentation for 5th graders tonight, so I have to be at my best. I'll respond now, and if necessary, I'll be more thorough 12 hours from now: Jeff: your question is my question too. I'm an amateur trying to figure this stuff out. When I built the viewer I was able to see for the first time that the correlation between northern hemisphere insolation and temperatures was visually striking for the Holocene and Eemian deglaciations, but not for the earlier two deglaciations in this data set. There are many areas to explore: e.g., see-saw effects that may delay warming in Antarctica? another Younger-Dryas like event? or perhaps there are errors in dating that magnify as you look at older ice. When I was studying the ice core data, I saw information on varying dating methods. I'll be exploring these. Mike: I'm eager to try out your program. I think it may be a great link to offer the kids I give astronomy presentations too. (I'm noticing an increase in kids asking what I think of global warming.) Mikemcc: thanks for the correction. I'll fix it. Marcus: I think the current theory is that orbital variations create differential heating of the high latitudes (north and south) that is more of a disturbance (rather than a change in over all heating) that can put more fresh water into the North Atlantic, changing ocean currents, which can release CO2 sequestered in the southern ocean (or reduce it's uptake of CO2); and then there are land changes such is deglaciation and lowered albedo, release of methane and carbon from northern tundra, permnafrost and bogs. One of my next steps is to get the average insolation values and see if they change much or if its mostly differential heating at work. RSVP: I will study your comment. My Earth, Orbit and Climate presentation includes mention of eccentricity affecting the time in season and that this was an earlier hypothesis superceded by Milankovitch. I think my reference for this is a Nature review article that I should cite as source. The release of oxygen tempering the effect of CO2 releases is new to me. I welcome more information on this. All: thanks for the time looking at my project and for your comments. jg
  9. Philippe Chantreau at 03:30 AM on 10 December 2010
    The Scientific Guide to Global Warming Skepticism
    Great work John, thanks.
  10. Stratospheric Cooling and Tropospheric Warming
    VeryTallGuy - 209 Ditto on your remark on understanding. I think the problem is that in the study of Physics, you go into tremendous detail over single individual entities. For example, I remember going into mindboggling details over a mere water molecule. Atmospheric science involves everything which is why it is so complex. I could understand a water molecule but when combined with all the other chemistry of the atmosphere and other factors such as the spinning of the planet, it all becomes extremely difficult and very tricky. This is why I really will not feel comfortable about my blog until it is blessed by a professional. And that's the problem here. All we hear about is ozone but it is not just ozone that is generating heat. Oxygen is also and probably other chemicals that we have never heard of. So I guess the bottom line is that ozone is not primarily responsible for the generation of heat in the upper atmosphere. Oxygen is responsible for that! I think in the upper atmosphere, there is more of the process that you labeled "1". Bob
  11. Stratospheric Cooling and Tropospheric Warming
    Bob @207 As I understand it (which is, painfully obviously, not all that well) there are several heat producing reactions with UV. 1) O2 is split: O2 = 2O (absorbing a photon of UV) 2) Ozone is created: 0+02=03 (releasing thermal energy) 3) Ozone is destroyed: O3 = 0 + O2 (absorbing a photon of UV) 4) Ozone is destroyed by other chemical reactions eg CFC catalysed At the top of the stratosphere you get more of (3) so despite absorbing quite a lot of UV, there isn't a very high Ozone conc. Each photon absorbed is a net energy & hence temp gain. Overall, there is more absorbed at top than bottom, hence the temp gradient. Lower down, the ratio changes hence the higher ozone concentration.
  12. Renewable Baseload Energy
    CBDunkerson Sorry. I thought you understood the meaning of albedo. End of discussion.
  13. It's cosmic rays
    Eric (skeptic) scientists study all the reasonable hypothesis, it's their job afterall. Problem is when people take those hypothesis as valid alternative theories. Note that the paper, although submitted, didn't show up. Here you can find a nice review which includes the same data shown in the arxiv paper.
  14. Renewable Baseload Energy
    RSVP writes: "What is positive feedback?" Reality. As opposed to your law of conservation of energy violating claim of heating the planet with solar hot water.
  15. The human fingerprint in the seasons
    I hate to bring this back to John's article but he's describing what a 'human fingerprint' would look like and comparing it to what a 'solar fingerprint' would look like. It's that comparison I'm trying to understand. I'm not saying "it's the sun" as Albatross says in #60, as I said before that's two steps forward. From what I can tell John's description of a solar fingerprint is essentially the direct effect from changes in TSI it ignores. 1) The GHG component, water vapour, of solar warming (non-contraversial but poorly constrained) 2) The top-down effect of UV (non-contraversial but poorly measured) 3) The role of CGR (contraversial) at the same time he seems to be ignoring the non-GHG component of a human fingerprint (albedo etc.). As i said before I think John is presenting this as an all or nothing scenario where 'human fingerprint' equals 'GHG fingerprint' and 'solar fingerprint' does not equal 'GHG fingerprint'. I put forward an alternative that solar has a 40-60% GHG component and the human fingerprint has a 66-100% component. I think his descriptions are too simplistic, in essence wrong. The question is whether the graph is as diagnostic as John seems to suggest when you factor in the feedbacks (and other stuff I mention). I'm asking the question and hoping for a reasonable explanation. I'm not putting forward any alternative theories for the warming.
  16. Ice data made cooler
    Thanks, this is pretty cool, but this isn't my field so my questions might seem simplistic. I see the asymetry in insolation you are talking about (although I don't understand how you infer (or know?) that from 400,000 years ago); there is also an asymetry at ~350-400kya and I don't see that correlating with increased temperature or CO2 levels. Can you explain this? Not arguing against this, just trying to understand it. I teach Biology at a community college and am trying to cover this better in my classes. Jeff
  17. Stratospheric Cooling and Tropospheric Warming
    mars - 203 Great reference document!
  18. Stratospheric Cooling and Tropospheric Warming
    VeryTallGuy - 205 But this is exactly what my dilemma is. Heat is being released in the ozone layer that is about one third of the way up the stratosphere. Shouldn't this layer, therefore, be the warmest part of the stratosphere? But it's not. The top of the stratosphere is the warmest part.
  19. Ice data made cooler
    John Nice piece of flash programming. I offer to you and others a project I designed a few years ago, funded by NSF, an interactive Flash-based game on global warming. It, too, is a work in progress but it is available at no cost "as is" online. www.globalwarminginteractive.com Feel free to use and distribute. Mike Hillinger
  20. Renewable Baseload Energy
    CBDunkerson What is positive feedback?
  21. Ice data made cooler
    Good stuff, John G. The power and impact of the visual presentation reveals itself time and again. This bit also was powerful:
    "I quickly learned that climate science was not an island surrounded by controversy, but a well-founded continent, and most critics I met were merely poor navigators."
     Great visuals and great word smithying! The Yooper
  22. Eric (skeptic) at 23:20 PM on 9 December 2010
    It's cosmic rays
    This paper seems appropriate to post here to compliment the new thread where it is postulated that the ends of ice ages are caused by increased solar forcing and CO2 feedback (with presumably the reverse for starting ice ages). GCR considered as a forcing is much more speculative http://arxiv.org/pdf/physics/0407005 and Kirkby et al say so. But what would be most interesting to me is to combine the orbital variation forcing (which is notably weak) with the GCR "sensitivity" modulation (see my post 26) to help explain rapid changes especially into ice ages. I put quotes around sensitivity since it is not the usual definition but a broader one in which any forcing (orbital solar or current CO2 increase) can be amplified or deamplified (or lowered forcing can also be amplified or deamplified).

    This may help explain some of the changes that are not explained by the orbital curves in the other thread, especially the initiation of warming and cooling since the GCR effects can be much more powerful (partly forcing as postulated in the paper, but also amplification of the weaker orbital forcing).

  23. The Scientific Guide to Global Warming Skepticism
    Thanks for the hard work. I will be sure to politely share this as much as possible.
  24. It's albedo
    You know, in the book "Jurassic Park", the chaos theorist character, Ian Malcolm, asserts that someone wearing black clothing will be just as comfortable as someone wearing a light color because of black body radiation. Really? I must have missed that, though it's been a long time since I read those books. Yes, Dr Malcolm is forgetting about the wavelength-dependence of absorptance and emissivity. Kind of surprising, given that people have known for a long time that dark-colored objects will heat up much faster in the sunlight than light-colored objects.
  25. Stratospheric Cooling and Tropospheric Warming
    VeryTallGuy 204 and 205 As there is no convection going on in the stratosphere and the layer is very stable it is not like the troposphere where the gases are well mixed but I am not over confident that my suggestion is correct in relation to molecular weights. It is however definitely related to the heights where different chemical reactions occur. The sad part is I read an article on the net about 2 weeks ago that explained the issue in detail and now I can't find it.
  26. Renewable Baseload Energy
    RSVP writes: "heat begets heat" And people wonder why we sometimes go off on 'skeptics'.
  27. Stratospheric Cooling and Tropospheric Warming
    Bob@201 And froom Wiki, "The stratosphere is layered in temperature because ozone (O3) here absorbs high energy UVB and UVC energy waves from the Sun and is broken down into monoatomic oxygen (O) and diatomic oxygen (O2). Monoatomic oxygen is found prevalent in the upper stratosphere due to the bombardment of UV light and the destruction of both ozone and diatomic oxygen. The mid stratosphere has less UV light passing through it, O and O2 are able to combine, and is where the majority of natural ozone is produced. It is when these two forms of oxygen recombine to form ozone that they release the heat found in the stratosphere. The lower stratosphere receives very low amounts of UVC, thus monoatomic oxygen is not found here and ozone is not formed (with heat as the byproduct)."
  28. Renewable Baseload Energy
    It appears that "warmists" would like the planet to be cooler, yet this scenario is only going to make renewable baseload energy sources less viable, since its only going to take more energy (not less) to overcome cold weather. The only way around this contradiction is to give up the idea of a cooler planet for a cleaner, warmer planet. For instance, using solar to warm water should not only warm homes, but the Earth in sum, as heat begets heat. Meanwhile, the warmer the planet, the less home heating needed, etc.
  29. We're heading into an ice age
    NQoA, so... the IPCC noting that Arctic sea ice extent has shown consistent declines over the past few decades translates in your mind to them claiming that it will show consistent declines every year going forward? I'm afraid that's a disconnect between your brain and reality. If you look at the past data you will see that it did not go down every single year then either. However, if you take the trend line for each decade it did indeed decline consistently each decade. Including the decade 2000-2009. The 2010-2019 decade has just started, but you'd have to be a fool to bet that it isn't going to show another decline below 2000-2009. The difference between the 'natural variability' which has always been part of AGW theory and that promoted by the 'skeptics' is that the variability considered in AGW scenarios actually exists... there are past precedents for it. The variability promoted by 'skeptics' exceeds all past experience and any possible explanation consistent with the laws of physics.
  30. Ice data made cooler
    Hi John just noted that the page displaying tghe triple point of water is showing it as 273K at 101kPa. It's actually 273K at 611Pa (right down just above the temperature axis line with that pressure scaling). CO2 is also 216K at 517kPa, so slightly lower than shown. Very good presentation though, and very timely as I'm involve in a discussion about this very subject.
  31. Stratospheric Cooling and Tropospheric Warming
    Bob @201 According to the lecture notes posted by Tom@186 yesterday, solar destruction of ozone generates heat at the top of the stratosphere. So I guess you'd expect less of it. mars @202, you wouldn't expect gases to stratify according to density, in the same way we don't have a layer of CO2 at the ground. It's just a balance of relative chemical destruction and creation of ozone according the intensity of radiation and concentration of other gases (eg ozone depletors) http://www.ess.washington.edu/Space/ESS205/upperatmweb.pdf
  32. Ice data made cooler
    The higher the eccentricity, the larger the difference in time (days) across the equinox line. The model should account for this. It should also account for the increase in release of other gases from oceans with temperature (such as oxygen), which would tend to temper the relative CO2 ppm values.
  33. It's albedo
    Tom, Ned, e, Yeah, Tom. I'm a bagpiper. Thanks for your help. Kirchoff's Law makes sense to me now. You know, in the book "Jurassic Park", the chaos theorist character, Ian Malcolm, asserts that someone wearing black clothing will be just as comfortable as someone wearing a light color because of black body radiation. Now, Crichton's written "State of Fear". I wonder if his misconception of black body radiation is an important factor in his views on global warming.
  34. Stratospheric Cooling and Tropospheric Warming
    Here is a basic course on the heat flows in the troposphere which explains how convection, latent heat and IR are transmitted to the troposphere. Atmospheric thermodynamics
  35. Stratospheric Cooling and Tropospheric Warming
    Most of the heat is generated by the chemical reaction of O+02->O3+ heat. We also have the reaction UV+O2->O+O. The ozone expels the heat as it is formed. So the highest density of ozone is not related to the highest temperature. As the O3 is heavier than O2 it will tend to sink to the bottom of the layer I think.
  36. Ice data made cooler
    So correct me if I'm wrong-as I understand it, as Earth's orbit brought it closer to the sun, temperatures began to rise. This, in turn, caused a release of CO2 into the atmosphere, which continued to drive temperatures upward long after the orbit had reached its nearest approach. Of course this time there is *no* orbital shift towards the sun (If anything, we should start moving *away* from the sun sometime in the next 20,000 years or so), so how do those contrarians explain the rise in CO2 & the accompanying rise in global temperatures? ;)
  37. Ice data made cooler
    Very nifty. Thanks John.
  38. Stratospheric Cooling and Tropospheric Warming
    Hi All, Please note that in the above diagram, the ozone layer is about one third of the way up in the stratosphere. The UV from the sun interacts with the ozone and heats up the stratosphere. But why isn't the temperature the highest where the ozone is densest which is about one third of the way up? Thanks, Bob
  39. Stratospheric Cooling and Tropospheric Warming
    Joe Blog 199 18:27 PM The atmosphere at low levels is transparent to nearly all of the incoming radiation. The atmosphere is heated by contact with the surface. As a result a parcel of air close to the ground forms which is warmer than the surrounding air. This parcel then expands making it less dense than the surrounding air and it starts to ascend cooling adiabatically. Simple put in the case of dry air it will cool at the rate 9.8 C per KM but the environmental lapse rate will be less than this so at some height the parcel will reach equilibrium with the local air mass and the parcel will stop rising. Thus heat from the surface is moved into the troposphere. This process is only marginally impacted on by radiation transfers. I hope we are not straying to far from the main topic here.
  40. 1934 - hottest year on record
    2007 is the warmest year based on the GHCN dataset. GHCN summary After the calendar flipping, I'll update that page for 2010.
  41. Stratospheric Cooling and Tropospheric Warming
    mars at 18:05 PM The point is, if the atmosphere was totally transparent, there wouldnt be convection... because radiation would simply pass through the atmosphere without interacting... So at low altitudes, where the atmosphere is opaque, convection is the dominant means of energy transfer, but as you rise through the troposphere, radiation, moves more and more of this energy, and less is moved through convection. Because the path length for the LW shortens. Put very simply, because there are less and less radiatively opaque molecules per volume. in the stratosphere, the atmosphere is opaque to UV, but less so to LW, so it does heat, and the upper levels do convect, but LW cooling from below causes the inversion, preventing convection.
  42. Stratospheric Cooling and Tropospheric Warming
    Tom the parcel of air in your example cools adiabatically (if non saturated) at a rate of 9.8 deg c per 1km and can rise at rates 300 meters per min. The cooling due to radiation is too slow and is normally ignored in weather forecasting of thermal heights.
  43. Stratospheric Cooling and Tropospheric Warming
    As a glider pilot I spent many hours studying the weather and using convection as a source of lift. I am fairly sure Tom is right as above.
  44. We're heading into an ice age
    NQuest @168, I have responded to your comment here so as not to distract from the topic of this thread.
  45. Arctic icemelt is a natural cycle
    Response to NQuest from the ice age thread> You're missing the point. None of those examples suggest that the changes will be monotonic year-after-year. When discussing global warming we are referring inherently to long term trends. Given the degree of annual variation, you need about 15 years to establish statistical significance. A 2-3 year trend means little to nothing with regard to the long term trends being discussed. This is a common misunderstanding among many skeptics and this same discussion has played out many many times on this site. It is in no way new or "sudden". The natural variation referred to is of the inter-annual short-term variety. If you take a look at the graph provided in this post, you can see clearly that there has been a clear downward trend extending from about 1970. You may also notice that there are many 2-3 year "recoveries" amidst this trend. It is because of this variability in the signal that you must look at 10+ years of data to make any claims about whether the ice is melting or growing over the long term.
  46. Stratospheric Cooling and Tropospheric Warming
    Tom Curtis at 17:41 exactly ;-)
  47. Stratospheric Cooling and Tropospheric Warming
    Joe Blog @191, I think I have completely misunderstood your point. Consequently, much of my discussion in 193 is irrelevant, so feel free to ignore it. If I have correctly understood your point now, it is this: A parcel of warm air in the lower atmosphere is surrounded by other parcels of air of similar temperature. Because the atmosphere is opaque to 15 micron radiation at that level, heat it radiates away is matched by heat absorbed from the neighbouring parcels of air. Consequently cooling by radiation is very inefficient at best, and the only way for the parcel of air to cool is to rise through the cooler air above it, thus driving convection. In constrast, once the parcel of air reaches about 8 km altitude, approximately half of the heat it radiates away radiates to outwards. In return, it receives very little energy from that direction, so radiation now effectively cools the parcel of air. This cooling deprives it of the ability to continue to rise by convection. Is this a fair statement of your view? And what corrections would you make, if any?
  48. Stratospheric Cooling and Tropospheric Warming
    Tom Curtis at 17:16 PM There is nothing you have written i really disagree with, the inversion is the reason for the cessation of convection, yes. Why is there an inversion? This is what i was getting at, if the atmosphere was optically thick at those altitudes, the downward radiation from the warmer higher layer, would heat the layers below, until they were in equilibrium. And with the continuing up ward flux from the top of the troposphere, it would revert to an adiabatic profile. If you add co2, it increases opacity, decreases radiative efficiency, meaning that you have to go higher, to a lower pressure, where the opacity will enable the transfer of energy...raising the tropopause... we agree on that as well. We are talking past each other, its a question of cause and effect, if there was no O3 absorption of UV, we wouldnt have an inversion, if the air above the tropopause was optically thick, but we had O3 absorption, we also would not have an inversion. There was a good conversation on one of the venus threads over at science of doom, that loosely covers this.
  49. NQuestofApollo at 17:32 PM on 9 December 2010
    We're heading into an ice age
    To Tom Curtis (164) - I was responding directly to post #127. If you are so inclined, please read #127 then read #161. If you still don't understand the point of my post, I will attempt to provide a better explanation.
  50. NQuestofApollo at 17:22 PM on 9 December 2010
    We're heading into an ice age
    To CBDunkerson (165) - following are three examples that support (in my opinion) the AGW promoters logic that accumulated CO2 would cause the sea ice extent to continue to decline: IPCC TAR 2001 The systematic decrease in spring and summer Arctic sea-ice extent in recent decades is broadly consistent with increases of temperature over most of the adjacent land and ocean. NASA 2003 "Researchers have suspected loss of Arctic sea ice may be caused by changing atmospheric pressure patterns over the Arctic that move sea ice around, and by warming Arctic temperatures that result from greenhouse gas buildup in the atmosphere. Warming trends like those found in these studies could greatly affect ocean processes, which, in turn, impact Arctic and global climate…As the oceans warm and ice thins, more solar energy is absorbed by the water, creating positive feedbacks that lead to further melting." And my favorite headline: Argentine glacier advances despite global warming June 2009 'We're not sure why this happens,' said Andres Rivera, a glacialist with the Center for Scientific Studies in Valdivia, Chile. 'But not all glaciers respond equally to climate change.' It is interesting to see AGW promoters suddenly embrace the "expected natural variation" explanation. That's pretty much what the "Climate Change Deniers" have been saying all along.

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